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Full text of "Alaskan glacier studies of the National Geographic Society in the Yakutat Bay, Prince William Sound and lower Copper River regions"

128
ALASKAN GLACIER STUDIES
quake shaking is that it is supplied by a long glacier from the north, which, flowing out upon the broad divide area, distributes its ice both to the east and to the west, and whose length is so great that the response to the earthquake shaking has not yet reached the two distributing arms. This does not seem probable to us.
BUTLER GLACIER
General Description. Back of the low mountain range on the north side of Nunatak Fiord lies the east end of the Orange through glacier. This was not visited in 1905 or 1906 and the exact conditions were misinterpreted. It was then thought that the eastern end of the Orange through glacier expanded beyond the mountain front in a broad, moraine-covered piedmont ice bulb. In 1909 we discovered that this eastern end of the
glacier actually terminates well within the mountain valley in a steeply-rising, moraine-covered ice front. This fact is further indication that the Orange through glacier is weak and is supplied from no very extensive sources. Otherwise it would necessarily extend at least to the end of its mountain valley. The eastern terminus of this glacier is evidently essentially stagnant, and its position is not materially different from what it was in 1905.
The moraine-covered piedmont ice bulb that was interpreted in 1905 and 1906 as an extension of the eastern end of the Orange through glacier was in 1909 found to be the piedmont bulb of Butler Glacier (Kg. 9), which descends from the mountains to the north. The Butler Glacier has not been studied within its mountain valley, and its conditions are, therefore, not known, but that it has considerable length, and a fairly-extensive supply, is indicated by the fact that it has been able to push itself out beyond the mountain front, whereas the much larger Orange Glacier has not been able to do so. In the view up the valley which we obtained we saw one good-sized hanging tributary and we also saw clear ice within the mountain valley.
The Bviler Glacier Bulb. The part of Butler Glacier beyond the mountain front possesses features of distinct interest. It spreads out in a stagnant bulb completely across the Orange Glacier through valley, and is separated from the Orange Glacier by a well-defined depression, though it is possible that in this depression, which we did not visit, the two glaciers coalesce. From this expanded bulb a good-sized glacial stream emerges and flows through a broad, deep gorge (PI. LVIE, B) cut in well-assorted, stratified gravels which rise almost vertically to a height of fully 100 feet. Beyond this gorge
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FIG. 9.    SKETCH OF BTJTLEE AND OBANGE GLACIERS.